Expedition ARA04C (conducted from September 10 - September 26, 2013 in Canadian waters) on the Korean icebreaker IBRV Araon was laid out to investigate the Beaufort Sea shelf and slope region and
collect geo-scientific data for various aspects relevant to the GSC's mandated regional geo-hazard assessment of the offshore Beaufort region. A critical element of the geohazards is the distribution of permafrost across the submerged shelf. To
address this question a set of six Ocean Bottom Seismometers (OBS) were deployed in a grid pattern across the near shelf-edge zone, and a set of three OBS was used in a second deployment along a central shelfcrossing north-east to south-west oriented
line. Initial data processing was carried out, which is required for any follow-up detailed velocity analysis. The processing included definition of exact shot times, geometry calculation, OBS position re-location, and OBS orientation analysis. A
preliminary analysis of the hydrophone and vertical-component data from the OBS stations reveals a P-wave-velocity structure with values ranging from 1800 m/s to over 4000 m/s indicative of wide-spread ice-bearing sediments. This open-file report
also contains the digital OBS data for all stations in standard SEGY format, together with the required raw and processed geometry information.

Summary

(Plain Language Summary, not published)Expedition ARA04C was conducted from September 10 to September 26, 2013 on the Korean icebreaker IBRV Araon in the Canadian Beaufort Sea. The expedition
was set out to collect scientific data for a regional geo-hazard assessment of the offshore Beaufort region. A critical element of the hazards is the distribution of permafrost across the shelf and slope region. To address this question a set of
Ocean Bottom Seismometers (OBS) were deployed to measure seismic velocities as indicator for ice-content in the sub-surface. This report describes the techncially required pre-processing steps (OBS relocation and orientation analyses) and includes an
initial compressional wave velocity analysis. The analysis of the hydrophone and vertical-component data from the OBS stations reveals a compressional wave-velocity structure with values ranging from 1800 m/s to over 4000 m/s indicative of
wide-spread ice-bearing sediments.